Certain medical treatments require implantation of one or more subcutaneous ports, such as vascular access ports. A port is typically composed of (i) a housing, which defines a reservoir; (ii) a self-sealing septum, which covers and fluidly seals the reservoir; and (iii) an outlet through which fluid can pass between the reservoir and a catheter attached to the port. The port outlet is typically connected to the proximal end of a catheter, with the distal tip of the catheter terminating at a target location within the body, such as the junction of the superior vena cava and the right atrium. Following implantation, the port reservoir can be fluidly accessed with a needle, such as a non-coring infusion set, providing the ability to infuse and aspirate fluid to and from the target location. The port housing is typically made from medical grade plastics or metals, and the septum is typically made of an elastomeric material such as silicone.
Port catheters that are indwelling for extended periods of time pose the risk that blood may reflux into the catheter where it can clot, occluding the catheter or port reservoir, and/or potentially leading to infection. To prevent reflux, a port may incorporate an internal valve, such as the PASV® Valve provided by AngioDynamics, Inc. (Latham, N.Y.). Internal valves typically include a valve element made from an elastomeric disk that has one or more slits therein. When a fluid pressure differential across the valve reaches a sufficient threshold, the valve element deforms so that the edges of the slit or slits are separated and fluid can flow across the valve. The pressure necessary to deform the valve element depends on variables which may include the thickness, shape, durometer, and elastic properties of the valve material being used.
Conventional valved ports typically include a valve housing configured within the port body for keeping the valve element secure. For example, referring to prior art FIG. 1, the port 10 housing defines a reservoir 40 that is fluidly sealed with a self-sealing septum 20. The port 10 also includes an outlet 45 and a flexible valve element 30 with a pressure activated slit 35 for regulating the flow of fluid between the reservoir and an attached catheter 15. The flexible valve element 30 can for example be circular, and secured within the port 10 by a valve housing 50 that circumferentially runs along the inner wall of the outlet 45 and includes some type of protrusion for securing edges of the valve element 30. The valve housing functions to secure the elastomeric element in place, so that it does not become compromised or dislodged during procedures requiring higher pressures and flow rates, such as power injection and dialysis. Since conventional valved ports require a valve housing for securing the elastomeric valve element, the profile and footprint of the port is increased relative to ports without valves. It would be desirable to provide a port that preserves the reflux-preventive qualities of conventional valved ports, with a decreased profile and footprint to improve patient comfort, while also minimizing the cost and complexity of manufacturing the valved port.